Tandem Z - selective cross metathesis – dihydroxylation for the synthesis of anti - 1 , 2 - diols

A stereoselective synthesis of anti-1,2-diols has been developed using a multitasking Ru-catalyst in an assisted tandem catalysis protocol. A cyclometalated ruthenium complex catalyzes first a Zselective cross metathesis of two terminal olefins followed by a stereospecific dihydroxylation. Both steps are catalyzed by Ru, as the Ru-complex is converted to a dihydroxylation catalyst upon addition of NaIO4. A variety of olefins are transformed into valuable highly functionalized and stereodefined molecules. Mechanistic experiments are performed to probe the nature of the oxidation step and catalyst inhibition pathways. These experiments point the way to more broadly applicable tandem catalytic transformations.